Copper will slump as the U.S. Federal Reserve starts to raise interest rates, demand growth stalls in China and stockpiles surge, according to Goldman Sachs Group Inc., which stood by a year-end forecast that signals the biggest annual drop since the global financial crisis.

Prices will probably drop to $4,800 a metric ton by the end of December and $4,500 at the end of next year, analysts including Max Layton and Jeffery Currie wrote in a report. The metal traded at $5,080 at 7:44 a.m. in London. A drop to Goldman’s end-2015 target implies a full-year retreat of 24 percent, the most since the 54 percent plunge in 2008.

“We see a long list of potential catalysts for copper’s next major move lower,” Layton, Currie and Yubin Fu wrote in the note received on Thursday. Of particular importance for copper has been the weakness in China, which points to a hard landing for commodities demand during 2015, they said.

Copper retreated along with nickel, zinc and crude oil this year as commodities were pummeled by the slowdown in the biggest user of base metals and excess supplies. While the retreat in copper prompted Glencore Plc to announce supply cuts at operations in Africa, Goldman said that such reductions served only as a confirmation that demand was weak. The New York-based bank said consumption in China wouldn’t grow at all this year, and forecast global surpluses of at least 500,000 tons from 2016 to 2019.

“We do not see these bearish drivers changing for some time, and as such producers are set to remain under pressure and likely to rationalize global production,” the analysts wrote. A fight between miners to cut costs as demand weakens would result in self-reinforcing cost and price deflation, echoing patterns seen in the bulk-commodity markets, the bank said.

There will be about 530,000 tons more global supply than demand in 2016, Goldman said, paring its estimate from about 670,000 tons. The worldwide surplus was seen at 566,000 tons in 2017, 626,000 tons in 2018 and 657,000 tons in 2019, it said.

The Fed refrained from the first increase in U.S. borrowing costs since 2006 this month amid concern that financial-market turmoil spurred by China’s slowdown may hurt the outlook for U.S. growth and inflation. Policy makers at the U.S. central bank would tighten in December, Goldman said.

Global stockpiles were seen increasing by as much as 1 million tons between November and March, Goldman said in the report, which was titled ‘Copper’s bear cycle still has years to run.’ Holdings in LME-tracked warehouses stood 327,175 tons as of Wednesday, according to bourse data.

Further losses in energy prices may also hurt copper, according to Goldman. There was potential for crude at $20 a barrel should storage constraints be beached, it said. Brent crude was at $48.24 on Thursday.

Copper will slump as the U.S. Federal Reserve starts to raise interest rates, demand growth stalls in China and stockpiles surge, according to Goldman Sachs Group Inc., which stood by a year-end forecast that signals the biggest annual drop since the global financial...